When using Track Motion, does it diminish quality of image?

[David Delaney]

I am curious about something because I am seeing it in my project. When I use Track Motion to move the image/view point around, I notice the image (still) seems to be blurrier and degraded because of this. Is this normal?

[Edward Troxel]

If you use Track Motion to ZOOM IN - yes, you will lose quality in a hurry. To zoom out or position the image, it should not lose quality. Just make sure you're using Pan/Crop when you zoom in.

Pan/Crop will zoom in using the full resolution of the image.
Track Motion will zoom in on the video frame.

[Graham Bernard]

Edward, please explain this to me? Of course I understand HOW I accomplish/do the two different methods. But in terms of what exactly is happening I have often wanted to ask this.

So:

Originally Posted by Edward Troxel

Pan/Crop will zoom in using the full resolution of the image.

. .and . . .

Originally Posted by Edward Troxel

Track Motion will zoom in on the video frame.

Also is this only a Preview loss but is it regained in the Render?

TIA

Grazie

[Mike Kujbida]

Grazie, Track Motion shrinks whatever you give to project size while Pan/Crop scales it down to project size while allowing you to zoom in using the original image size.
For example, you bring a 3000 x 2000 pixel image into your project.
Assuming you're working in SD size, Track Motion shrinks this image to 720 x 576. This is OK for panning and moving the image around. Just don't try to zoom in on the image as it's been shrunk down to the new smaller size.
On the other hand, Pan/Crop scales it down to the new size leaving the original image dimensions available for zooming in on a portion of it.

Hopefully this makes sense.

[Richard Hunter]

Hi Grazie. The way I understand it is this.

With TM, Vegas resizes (or scales, same thing) the video to project resolution before applying the TM, so it's downhill all the way from there if you zoom in.

PC crops the image using its full resolution, and then the cropped portion is resized to project size.

Richard

[Edward Troxel]

Say I'm working with NTSC DV. And say you have an image that's 3000x2000 pixels and you wish to zoom in to a small area in the middle of the screen. Suppose you're zooming in so far that you're throwing away 2/3 of the picture to get to the area you really want. (i.e. you're looking at 800 pixels wide in the image and the other 2200 pixels in the original image are off the screen so it's now scaling 800 pixels to 720).

So we're zooming WAY in on the image. With Pan/Crop, we're looking at the original 800 pixels with the 2200 being off the screen. So you get a a great looking zoom because Pan/Crop uses the full resolution of the image while it zooms.

The video output is 720x480. Originally the 3000x2000 image is scaled to fit that 720x480 window. When you use Track Motion, it deals with that 720x480 video frame - NOT the full image. So now zoom in the same distance... You've now blown up 192 video frame pixels to fill up the full 720 width adding LOTS of blur. And quality will NOT be regained upon rendering. The blurry image you see on the screen is the same blurry image you will get upon rendering.

Give it a try. Pop two images on the timeline on two tracks. Zoom in identically on both of them - one track using Track Motion and the other track using Pan/Crop. Zoom in a long way to exaggerate the different. If you want to check the rendering differences, render it out and then put that new render on a new timeline and compare the two. I think you'll find a dramatic difference between the two.

[David Delaney]

I am using it primarily for odd shaped photographs in a slideshow presentation - to get rid of the borders of the photo because they are not 720X540, I need to use the Track Motion to zoom in slightly and this is when I noticed the blur and fuzziness creeping in. I suppose it is the nature of the beast when working with photos that don't fit the regular 16:9 image....

[Edward Troxel]

David. Here's your solution.

Drop the image on the timeline, open Pan/Crop, then right-click on the image and choose "Match Output Aspect". Adjust to suit and you're done.

Stay away from Track Motion for this purpose.

Remember that scripts are available that can set the "Match Output Aspect" on all selected images at once.

[David Delaney]

The problem is that Match Aspect ratio will stretch images and distort them...

[Edward Troxel]

Originally Posted by David Delaney

The problem is that Match Aspect ratio will stretch images and distort them...

huh?????????

It won't stretch the images. It will just make the size of the pan/crop frame match the same shape/aspect of the output.

[David Delaney]

Really? Are you talking about MAINTAIN ASPECT RATIO? Whenever I use maintain aspect ratio (clicking on NO), if the picture doesn't fill the frame, making it NO stretches the image to fill the frame.

Ok I get it, it is RIGHT CLICK to get match output. Darn it! I did the whole project the other way and I don't want to go back and fix it at this point. Lesson learned.

[David Delaney]

Hey Ed,

Thanks for all the help. Now, out of curiosity, how much of a difference or how much degradation am I going to experience using the Track motion vs the Pan/Crop?

[Edward Troxel]

Yeah, the right-click and "Match Output Aspect" is what I'm talking about. Here's some examples to show you the difference between the three:

Image 1: The original image simply dropped onto the timeline
Image 2: Using Pan/Crop - set the "Match Output Aspect" - and zoomed in on the horse's head.
Image 3: Using Track Motion to zoom in on the horse's head

I believe you'll immediate see the difference between these two zooms.

[David Delaney]

Wow, what a difference. Nuff said. I have gone back and changed almost all of the images to Pan/Crop even though I loathed to do it. I am not zooming in that much, but I would prefer to have it look crisp - I will only use motion for movements.

[Edward Troxel]

I zoomed way in to somewhat exaggerate the difference. However, there may certainly be times you WANT to zoom in that far.

I'm a big fan of using the tools for what they were designed to do: Pan/Crop for panning and cropping (i.e. zooming IN on the images) and Track Motion for positioning/creating PIPs (essentially zooming OUT).